Connective Tissue
Dr. Amam Ali Amam
PhD: Periodontal Disease
How are we going to study
connective tissue?
• Study connective tissue components
• Focus on different cell types characters
and properties
• Where and when to find these cells.
What’ r we going to study in these
cells
1. Properties, characterization and shape
2. Function.
3. Origin (from where they are derived?)
The human body is composed of only
4 basic types of tissue
Epithelial
tissue
Connective
tissue
Muscular
tissue
Nervous
tissue
They are formed by:
Cells
Molecules
of the extracellular matrix
The main characteristics of these basic types
of tissue:
Tissue
Cells
Extracellular
matrix
Main
Function
Nervous
Intertwining elongated None
processes
Transmission of
nervous
impulses
Epithelial
Aggregated polyhedral Very small amount Lining of surface
cells
or body cavities,
glandular
secretion
Muscle
Elongated contractile
cells
Moderate amount
Movement
Connective
Several types of fixed
and wandering cells
Abundant amount Support and
protection
Epithelial, Muscle & Nerve
Tissues
are formed mainly by:
Cells
Connective Tissue
The major constituent is:
Extracellular
matrix
Connective Tissue
Characterized by:
The abundance of extracellular
material produced by its cells.
Present in all systems
Specialized connective tissue:
1- Adipose tissue.
2- Cartilage.
3- Bone.
Originate from the mesenchyme.
The mesenchyme develops from middle layer
of the embryo
Connective Tissues
Definition:
They are responsible for providing and
maintaining form in the body.
Function:
They are providing the matrix that:
1- connects .
2- binds the cells & organs,
3- gives support to the body.
Connective Tissues
Components & Function
• Fibroblasts: Fibroblasts and Fibrocyte, Other cells
• Fibers: structure & the most resistant componant of stroma.
In some organs they form walls & the trabecular .
• Ground substance:
macromolecules & multiadhesive glycoproteins.
– They are the storage of controls of the cells.
– Medium for nutrition and wastes.
Structure of Connective Tissue
3 classes of components
1- Cells
1-Fibroblast.
2-Macrophage.
3-Mast cell.
4-Plasma cell.
5-Lymphocytes.
6-Leukocytes.
7-Adipose cell.
2- Fibers
Reticular
Elastic
Collagen
Extracellular
matrix
3- Ground
substance
macromolecules
multiadhesive
glycoproteins
Extracellular matrices
Consist of different combinations of:
1- Protein Fibers
Collagen
Reticular
Elastic
Elastin = Amine Acid + Cholesterol
2- Ground
substance
macromolecules
multiadhesive
glycoproteins
Cells seen in connective tissue
1-Fibroblast.
2-Macrophage.
3-Mast cell.
4-Plasma cell.
5-Lymphocytes.
6-Leukocytes.
7-Adipose cell.
Fibers composed of:
Collagen
Constitute
Tendons
Aponeuroses
Capsules of
organs
Membranes
That envelop CNS
(meninges)
Fibroblast properties:
Synthesize collagen, elastin, glycosaminoglycans,
protyoglycans, and multiadhesiveprotiens.
The most common cells in the connective tissue
and most important.
They can go from resting to activating phase
depending on:
Stimulation such as: body injury (inflammation, trauma).
Involved in the production of growth factors, etc.
Fibroblast
The comparison between
Fibroblasts (active) & Fibrocytes
(rest)
The quiescent Fibroblasts (Fibrocyte)
Smaller than the active Fibroblasts.
Spindle shape.
Fewer processes.
Darker.
Elongated nucleus.
Acidophilic cytoplasm.
Small amount of rough endoplasmic reticulum.
Fibroblasts & Fibrocytes
Active
Quiescent
Function of connective tissue cells
Cell Type
Representative Product or Activity
Representative
Function
Fibroblast,
chondroblast,
Osteoblast.
Production of fibers & ground substance
Structural
Plasma cell
Production of antibodies.
Immunological
(defense)
Lymphocyte
(several types)
Production of immunocompetent cells
Immunological
(defense)
Eosinophilic
leukocyte
Participation in allergic & vasoactive reactions,
modulation of mast cell activities and the
inflammatory process.
Immunological
(defense)
Neutrophilic leukocyte
Phagocytosis of foreign substances, bacteria
Defense.
Macrophage
Secretion of cytokines and other molecules,
phagocytosis of foreign substances and bacteria,
antigen processing and presentation to other cells.
Defense.
Mast cell &
basophilic leukocyte
Liberation of pharmacologically active molecules
(eg, histamine)
Defense
Adipose (fat) cell
Storage of neutral fats.
Energy
reservoir, heat
production.
(participate in
allergic reactions
Connective tissue cells
Connective tissue cells
Function of connective tissue cells
Cell Type
Location
Main Function
Monocyte
Blood
Precursor of macrophages
Macrophage
Connective tissue,
Lymphoid organs, Lungs,
Bone marrow
Production of cytokines,
chemotactic factors, and several
other molecules that participate in
inflammation (defense), antigen
processing and presentation.
Kupffer cell
Liver
Same as macrophages.
Microglia cell
Nerve tissue of the CNS
Same as macrophages.
Langerhans cell
Skin
Antigen processing and presentation.
Dendritic cell
Lymph nodes
Antigen processing and presentation.
Osteoclast.
Bone (fusion of several
macrophages)
Digestion of bone.
Multinuclear
giant cell
Connective tissue (fusion
of several macrophages).
Segregation and digestion of
foreign bodies,
Macrophage
Characterization
Property& shape
Surface: irregular.
The cytoplasma: granular
Nucleus: oval eccentric nucleus
or kidney.
Age: long life.
Function
A phagocytic ability
&
Secrete cytokines
Origin (derived)
Defense.
Bone marrow, then from monocytes
then immigrates to connective tissue
Special names of Macrophage
Kupffer cell in the Liver.
Microglial cells in the CNS.
Langerhans cells of the Skin.
Osteoclasts in Bone tissue.
Monocytes & Macrophage
are the same cell in
different stages of maturation.
Distributed throughout the body & constitute
the
mononuclear phagocyte system
Macrophage
Macrophage
Mast cell
Cells: Round to oval.
Characterization The cytoplasma: filled with
basophilic granules.
Property& shape
Nucleus: spherical centric.
storage of mediators of the
inflammatory response.
&
Function
liberation of pharmacologically active
molecules.
Defense as allergic reaction.
Bone marrow (from progenitor cells),
Origin (derived) then immigrates to connective tissue.
Mast cell
Mast cell
The surface of mast cells contains specific receptors for
immunoglobulin E ( IgE).
IgE is a type of immunoglobulin produced by Plasma cells.
Mast cell
Plasma cell
Characterization
Property& shape
Function
Origin (derived)
Cells: large & ovoid .
The cytoplasm: basophilic.
Nucleus: spherical eccentric, with
dense compact chromatin.
Age: short life (10-20 days).
Synthesis of antibodies.
Defense (immunological).
B lymphocyte.
Plasma cell
Plasma cell
Lymphocytes, Leukocytes
( white blood corpuscles)
Characterization
Property& shape
to be discussed later ( lymphoid
organs).
Defense: when there is
Function
inflammation they immigrates to
connective tissue
Origin
(derived)
Bone marrow (they migrate from
the blood vessels by diapedesis).
Collagen fibers
Basesd on their structure & functions
they can classified into 4 groups
1-Collagen that form long fibrils
2- Fibril- associated Collagen.
3-Collagen that form a network
4-Collagen that form anchoring fibrils
Collagen fibers
Elastin fibres
Elastin fibres
Reticular fibres
Ground substance
3 classes of components
Glycosaminoglycans
Called
acid mucopolysaccharides
Proteoglycans
a core protein with
4 main Glycosaminoglycans
1- dermatan sulfate.
2- chondroitin sulfate.
3- keratan sulfate.
4- heparan sulfate.
multiadhesive
glycoproteins
Adipose tissue
Characterization, Property& shape
Adipose tissue is a special connective tissue in which
adipose cells predominate.
Often called Fat cells.
Adipose cells (Adipocytes) predominate.
Isolated in small groups within connective tissue or found in
large aggregates.
It’s one of the largest tissue in the body.
In men 15-20 % of the body weight.
In women 20-25 % of the body weight.
It’s a very efficient storage tissue.
Fills up spaces between other tissues, keep some organs
in place.
Both types of adipose tissue have a rich blood supply.
It spreads all over the body.
Adipose tissue
Functions
It is the largest storage of energy of the body
(triglycerides), the other organs are liver & skeletal
muscle (glycogen).
Energy reservoir, heat production.
Types of Connective Tissue
Section of Loose Connective Tissue Proper
Section of Loose Connective Tissue Proper
Section of immature dense irregular Connective Tissue Proper
Longitudinal section of dense regular Connective Tissue
Dense supporting tissue
Mucous Tissue of an embryo
Adipose tissue
Adipose tissue
1- Unilocular adipose 2- Multilocular adipose
Tissue
tissue
brown
Common or yellow
1- Unilocular adipose tissue
Common or yellow
Color: white to dark yellow.
Characterization Distribution : all the body except the eyelids, the
Property& shape scrotum, etc.
Uniform: In newborn has a uniform thickness
throughout the body.
Cells: spherical (if isolated), polyhedral (in adipose
tissue, closely packed).
The cytoplasm: thin ring (single ring cell), contains
a Golgi complex, mitochondria, free polyribosomes.
Nucleus: eccentric & flattened.
Surrounded by a basal lamina.
Function
Origin (derived)
In Starving and Obesity: release or storing fat ,
that’s mean, cell size differs not cells numbers!
Lipoblast from ( Mesenchymal cell).
Unilocular adipose tissue
Unilocular & Multilocular
adipose tissue, Origin (derived)
2- Multilocular adipose tissue
Brown fat
Cell: Polygonal and smaller cells (than Unilocular) .
Nucleus: spherical & central.
Color & Called : Brown fat (large number of blood
capillaries & numerous mitochondria (colored
Characterization
cytochromes).
Property& shape
The cytoplasm: great number of lipid droplets
(various sizes).
Distribution: Limited ( animals; hibernating gland).
Function
Origin (derived)
Produce heat.
In newborn and hibernating animals:
to raise the body heat as this tissue is a wellinnervated tissue.
Lipoblast from ( Mesenchymal cell).
mesenchemical cells that resemble epithelial cells.
Distribution of adipose tissue
Multliocular adipose tissue
in a human newborn
Multiocular adipose Tissue
Brown adipose tissue